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Fri, 21 Apr 2023 19:32:34 +0200 Content-Type: multipart/mixed; boundary="------------Uz7N2hSro1BXgYQbTl7hDQWx" Message-ID: Date: Fri, 21 Apr 2023 19:32:25 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.10.0 Subject: Re: [PATCH v3 03/11] documentation: Block Devices Snapshots Module Content-Language: en-US From: Sergei Shtepa To: Donald Buczek , , , , CC: , , , , , , , , , , , References: <20230404140835.25166-1-sergei.shtepa@veeam.com> <20230404140835.25166-4-sergei.shtepa@veeam.com> <86068780-bab3-2fc2-3f6f-1868be119b38@veeam.com> <1dc227d0-9528-9b77-63ff-b49b0579caa1@molgen.mpg.de> <955ede49-bb69-2ab2-d256-a329fe1b728c@molgen.mpg.de> <3b589d44-3fbd-1f4f-8efb-9b334c26a20f@molgen.mpg.de> In-Reply-To: X-Originating-IP: [172.24.10.107] X-ClientProxiedBy: prgmbx02.amust.local (172.24.128.103) To prgmbx01.amust.local (172.24.128.102) X-EsetResult: clean, is OK X-EsetId: 37303A2924031554677065 X-Veeam-MMEX: True X-Spam-Status: No, score=-5.4 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --------------Uz7N2hSro1BXgYQbTl7hDQWx Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit On 4/20/23 21:17, Sergei Shtepa wrote: > Subject: > Re: [PATCH v3 03/11] documentation: Block Devices Snapshots Module > From: > Sergei Shtepa > Date: > 4/20/23, 21:17 > > To: > Donald Buczek , axboe@kernel.dk, hch@infradead.org, corbet@lwn.net, snitzer@kernel.org > CC: > viro@zeniv.linux.org.uk, brauner@kernel.org, willy@infradead.org, kch@nvidia.com, martin.petersen@oracle.com, vkoul@kernel.org, ming.lei@redhat.com, gregkh@linuxfoundation.org, linux-block@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org > > > > On 4/20/23 16:44, Donald Buczek wrote: >> Subject: >> Re: [PATCH v3 03/11] documentation: Block Devices Snapshots Module >> From: >> Donald Buczek >> Date: >> 4/20/23, 16:44 >> >> To: >> Sergei Shtepa , axboe@kernel.dk, hch@infradead.org, corbet@lwn.net, snitzer@kernel.org >> CC: >> viro@zeniv.linux.org.uk, brauner@kernel.org, willy@infradead.org, kch@nvidia.com, martin.petersen@oracle.com, vkoul@kernel.org, ming.lei@redhat.com, gregkh@linuxfoundation.org, linux-block@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org >> >> >> On 4/19/23 21:42, Donald Buczek wrote: >>> Dear Sergei, >>> >>> On 4/19/23 15:05, Sergei Shtepa wrote: >>>> [...] >>>> >>>> Patches in attach and https://github.com/SergeiShtepa/linux/tree/blksnap-master >>> Thanks. I can confirm that this fixes the reported problem and I no longer can trigger the UAF. ???? >>> >>> Tested-Bny: Donald Buczek >>> >>> Maybe you can add me to the cc list for v4 as I'm not subscribed to the lists. >> >> Sorry, found another one. Reproducer: >> >> ===== >> #! /bin/bash >> set -xe >> modprobe blksnap >> test -e /scratch/local/test.dat || fallocate -l 1G /scratch/local/test.dat >> s=$(blksnap snapshot_create -d /dev/vdb) >> blksnap snapshot_appendstorage -i $s -f /scratch/local/test.dat >> blksnap snapshot_take -i $s >> s2=$(blksnap snapshot_create -d /dev/vdb) >> blksnap snapshot_destroy -i $s2 >> blksnap snapshot_destroy -i $s >> ===== >> >> >> [20382.402921] blksnap-snapshot: Snapshot ff1c54f1-3e8c-4c99-bb26-35e82dc1c9fa was created >> [20382.535933] blksnap-image: Create snapshot image device for original device [253:16] >> [20382.542405] blksnap-snapshot: Snapshot ff1c54f1-3e8c-4c99-bb26-35e82dc1c9fa was taken successfully >> [20382.572564] blksnap-snapshot: Snapshot 4b2d571d-9a24-419d-96c2-8d64a07c4966 was created >> [20382.600521] blksnap-snapshot: Destroy snapshot 4b2d571d-9a24-419d-96c2-8d64a07c4966 >> [20382.602373] blksnap-snapshot: Release snapshot 4b2d571d-9a24-419d-96c2-8d64a07c4966 >> [20382.722137] blksnap-snapshot: Destroy snapshot ff1c54f1-3e8c-4c99-bb26-35e82dc1c9fa >> [20382.724033] blksnap-snapshot: Release snapshot ff1c54f1-3e8c-4c99-bb26-35e82dc1c9fa >> [20382.725850] ================================================================== >> [20382.727641] BUG: KASAN: wild-memory-access in snapshot_free+0x73/0x170 [blksnap] >> [20382.729326] Write of size 8 at addr dead000000000108 by task blksnap/8297 >> ... > Great! Thanks. > > There is no protection against re-adding a block device to the snapshot. > I'll take care of it. > Hi! I think the fix turned out to be quite beautiful. Now you will get an error "Device or resource busy". Fix in attach and on github. Link: https://github.com/SergeiShtepa/linux/commit/43a5d3dd9858f092b734187b6a62ce75acaa47c7 --------------Uz7N2hSro1BXgYQbTl7hDQWx Content-Type: text/x-patch; charset="UTF-8"; name="fix_no_protection_re-adding.patch" Content-Disposition: attachment; filename="fix_no_protection_re-adding.patch" Content-Transfer-Encoding: base64 ZGlmZiAtLWdpdCBhL2RyaXZlcnMvYmxvY2svYmxrc25hcC9zbmFwc2hvdC5jIGIvZHJpdmVy cy9ibG9jay9ibGtzbmFwL3NuYXBzaG90LmMKaW5kZXggMWYyOGZmNTlkNzYyLi44MDYzY2M0 YjkyOWUgMTAwNjQ0Ci0tLSBhL2RyaXZlcnMvYmxvY2svYmxrc25hcC9zbmFwc2hvdC5jCisr KyBiL2RyaXZlcnMvYmxvY2svYmxrc25hcC9zbmFwc2hvdC5jCkBAIC0yOCw3ICsyOCw3IEBA IHN0YXRpYyB2b2lkIHNuYXBzaG90X2ZyZWUoc3RydWN0IGtyZWYgKmtyZWYpCiAKIAkJdHJh Y2tlciA9IGxpc3RfZmlyc3RfZW50cnkoJnNuYXBzaG90LT50cmFja2Vycywgc3RydWN0IHRy YWNrZXIsCiAJCQkJCSAgIGxpbmspOwotCQlsaXN0X2RlbCgmdHJhY2tlci0+bGluayk7CisJ CWxpc3RfZGVsX2luaXQoJnRyYWNrZXItPmxpbmspOwogCQl0cmFja2VyX3JlbGVhc2Vfc25h cHNob3QodHJhY2tlcik7CiAJCXRyYWNrZXJfcHV0KHRyYWNrZXIpOwogCX0KQEAgLTE2MCwx NCArMTYwLDE3IEBAIGludCBzbmFwc2hvdF9hZGRfZGV2aWNlKGNvbnN0IHV1aWRfdCAqaWQs IHN0cnVjdCB0cmFja2VyICp0cmFja2VyKQogCQl9CiAJfQogCWlmICghcmV0KSB7Ci0JCXRy YWNrZXJfZ2V0KHRyYWNrZXIpOwotCQlsaXN0X2FkZF90YWlsKCZ0cmFja2VyLT5saW5rLCAm c25hcHNob3QtPnRyYWNrZXJzKTsKKwkJaWYgKGxpc3RfZW1wdHkoJnRyYWNrZXItPmxpbmsp KSB7CisJCQl0cmFja2VyX2dldCh0cmFja2VyKTsKKwkJCWxpc3RfYWRkX3RhaWwoJnRyYWNr ZXItPmxpbmssICZzbmFwc2hvdC0+dHJhY2tlcnMpOworCQl9IGVsc2UKKwkJCXJldCA9IC1F QlVTWTsKIAl9CiAJdXBfd3JpdGUoJnNuYXBzaG90LT5yd19sb2NrKTsKIAogCXNuYXBzaG90 X3B1dChzbmFwc2hvdCk7CiAKLQlyZXR1cm4gMDsKKwlyZXR1cm4gcmV0OwogfQogCiBpbnQg c25hcHNob3RfZGVzdHJveShjb25zdCB1dWlkX3QgKmlkKQpkaWZmIC0tZ2l0IGEvZHJpdmVy cy9ibG9jay9ibGtzbmFwL3RyYWNrZXIuYyBiL2RyaXZlcnMvYmxvY2svYmxrc25hcC90cmFj a2VyLmMKaW5kZXggZDk4MDQ4ZGM1YmVkLi4wMDhjYzdmMGY4MWUgMTAwNjQ0Ci0tLSBhL2Ry aXZlcnMvYmxvY2svYmxrc25hcC90cmFja2VyLmMKKysrIGIvZHJpdmVycy9ibG9jay9ibGtz bmFwL3RyYWNrZXIuYwpAQCAtNzksNiArNzksNyBAQCBzdGF0aWMgc3RydWN0IGJsa2ZpbHRl ciAqdHJhY2tlcl9hdHRhY2goc3RydWN0IGJsb2NrX2RldmljZSAqYmRldikKIAkJcmV0dXJu IEVSUl9QVFIoLUVOT01FTSk7CiAJfQogCisJbXV0ZXhfaW5pdCgmdHJhY2tlci0+Y3RsX2xv Y2spOwogCUlOSVRfTElTVF9IRUFEKCZ0cmFja2VyLT5saW5rKTsKIAlrcmVmX2luaXQoJnRy YWNrZXItPmtyZWYpOwogCXRyYWNrZXItPmRldl9pZCA9IGJkZXYtPmJkX2RldjsKQEAgLTIz NCwxMiArMjM1LDE3IEBAIHN0YXRpYyBpbnQgKCpjb25zdCBjdGxfdGFibGVbXSkoc3RydWN0 IHRyYWNrZXIgKnRyYWNrZXIsCiBzdGF0aWMgaW50IHRyYWNrZXJfY3RsKHN0cnVjdCBibGtm aWx0ZXIgKmZsdCwgY29uc3QgdW5zaWduZWQgaW50IGNtZCwKIAkJICAgICAgIF9fdTggX191 c2VyICpidWYsIF9fdTMyICpwbGVuKQogeworCWludCByZXQgPSAwOwogCXN0cnVjdCB0cmFj a2VyICp0cmFja2VyID0gY29udGFpbmVyX29mKGZsdCwgc3RydWN0IHRyYWNrZXIsIGZpbHRl cik7CiAKIAlpZiAoY21kID4gQVJSQVlfU0laRShjdGxfdGFibGUpKQogCQlyZXR1cm4gLUVO T1RUWTsKIAotCXJldHVybiBjdGxfdGFibGVbY21kXSh0cmFja2VyLCBidWYsIHBsZW4pOwor CW11dGV4X2xvY2soJnRyYWNrZXItPmN0bF9sb2NrKTsKKwlyZXQgPSBjdGxfdGFibGVbY21k XSh0cmFja2VyLCBidWYsIHBsZW4pOworCW11dGV4X3VubG9jaygmdHJhY2tlci0+Y3RsX2xv Y2spOworCisJcmV0dXJuIHJldDsKIH0KIAogc3RhdGljIHN0cnVjdCBibGtmaWx0ZXJfb3Bl cmF0aW9ucyB0cmFja2VyX29wcyA9IHsKZGlmZiAtLWdpdCBhL2RyaXZlcnMvYmxvY2svYmxr c25hcC90cmFja2VyLmggYi9kcml2ZXJzL2Jsb2NrL2Jsa3NuYXAvdHJhY2tlci5oCmluZGV4 IGQwOTcyOTk0ZDUyOC4uZGJmODI5NWY5NTE4IDEwMDY0NAotLS0gYS9kcml2ZXJzL2Jsb2Nr L2Jsa3NuYXAvdHJhY2tlci5oCisrKyBiL2RyaXZlcnMvYmxvY2svYmxrc25hcC90cmFja2Vy LmgKQEAgLTE5LDYgKzE5LDkgQEAgc3RydWN0IGRpZmZfYXJlYTsKICAqCiAgKiBAZmlsdGVy OgogICoJVGhlIGJsb2NrIGRldmljZSBmaWx0ZXIgc3RydWN0dXJlLgorICogQGN0bF9sb2Nr OgorICoJVGhlIG11dGV4IGJsb2NrcyBzaW11bHRhbmVvdXMgbWFuYWdlbWVudCBvZiB0aGUg dHJhY2tlciBmcm9tIGRpZmZlcmVudAorICoJdHJlYWRzLgogICogQGxpbms6CiAgKglMaXN0 IGhlYWRlci4gQWxsb3dzIHRvIGNvbWJpbmUgdHJhY2tlcnMgaW50byBhIGxpc3QgaW4gYSBz bmFwc2hvdC4KICAqIEBrcmVmOgpAQCAtNDEsNiArNDQsNyBAQCBzdHJ1Y3QgZGlmZl9hcmVh OwogICovCiBzdHJ1Y3QgdHJhY2tlciB7CiAJc3RydWN0IGJsa2ZpbHRlciBmaWx0ZXI7CisJ c3RydWN0IG11dGV4IGN0bF9sb2NrOwogCXN0cnVjdCBsaXN0X2hlYWQgbGluazsKIAlzdHJ1 Y3Qga3JlZiBrcmVmOwogCWRldl90IGRldl9pZDsK --------------Uz7N2hSro1BXgYQbTl7hDQWx--